Alzheimer's - What Causes Alzheimer's Disease

Alzheimer's disease is a group disorders involving the parts of the brain that control thought, memory, and language. It is marked by progressive deterioration, which affects both the memory and reasoning capabilities of an individual.

Causes and Risk Factors

Scientists do not yet fully understand what causes Alzheimer's disease. There probably is not one single cause, but several factors that affect each person differently. Age is the most important known risk factor for Alzheimer's disease. The number of people with the disease doubles every 5 years beyond age 65.

Symptoms

Memory and the ability to think clearly are gradually lost over time. There may also be a change in personality. Someone who used to be a calm person may become agitated or upset more easily, for example. Behaviour problems and communication difficulties may also occur.

People with severe Alzheimer's may find it difficult to perform everyday tasks, such as dressing, washing and eating. As time passes they may not recognise people or their surroundings, so it's common for them to go for a walk and get lost. Other problems, such as depression, may also develop.

Treatments and drugs

Currently, there's no cure for Alzheimer's disease. Doctors sometimes prescribe drugs to improve symptoms that often accompany Alzheimer's, including sleeplessness, wandering, anxiety, agitation and depression. But only two varieties of medications have been proved to slow the cognitive decline associated with Alzheimer's.

Cholinesterase inhibitors

This group of medications — which includes donepezil (Aricept), rivastigmine (Exelon) and galantamine (Reminyl) — works by improving the levels of neurotransmitters in the brain. Donepezil has been approved by the Food and Drug Administration for the treatment of mild, moderate and severe Alzheimer's disease.

Donepezil also appears to delay the onset of Alzheimer's for about a year in people who have mild cognitive impairment (MCI). People who have MCI have more memory problems than other people their age, but they are not demented.

Cholinesterase inhibitors don't work for everyone. As many as half the people who take these drugs show no improvement. Other people may choose to stop taking the drugs because of the side effects, which include diarrhea, nausea and vomiting.

Memantine (Namenda)

The first drug approved to treat moderate to severe stages of Alzheimer's, memantine (Namenda), protects brain cells from damage caused by the chemical messenger glutamate. It sometimes is used in combination with a cholinesterase inhibitor. Memantine's most common side effect is dizziness, although it also appears to increase agitation and delusional behavior in some people.